<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>debugger</title>
</head>
<body>
    <script>
        var fn;
        function foo() {
            var a = 2;
            function baz() {
                console.log( a );
            }
            fn = baz;
        }
        function bar() {
            fn();
        }

        foo();
        bar();  // 2

    </script>
</body>
</html>